1. Field of the Invention
In the manufacturing process of optical disks, it has been commonly practiced to record a serial number, lot number, etc. on each optical disk in the form of a barcode.
2. Related Art of the Invention
Since such information cannot be written to a pit information area of the optical disk, it has been practiced to write the barcoded information to a non-information area, or unused space, on the optical disk.
When reproducing (playing back) such an optical disk, the pit information is read by an optical pickup; to read the barcoded information such as a serial number, etc. recorded in the non-information area, however, a separate reading device has been used.
In the above prior art optical disk, since information carrying a serial number and the like is not recorded in a pit area but recorded in a non-information area, as described above, a separate reading device has had to be provided in addition to the usual optical pickup, the resulting problem being increased complexity of the playback apparatus construction.